# chapter 1 : the set theory

**Objectives:**

After the lesson, the student will be able to:

Internalize the definition of terms related to Set Theory.

Understand some basic concepts in Set Theory, describing sets, elements, Venn diagrams and the union and intersection of sets.

Construct and use Venn diagrams to show subsets, complements, and the intersection and union of sets.

Solve problems involving the use of Venn diagrams for not more than three sets.

Instructions : Reading every topic carefully is a must. Internalize the topics included, There would be exercises and chapter quiz to be answered right after every topic. Before proceeding to the next chapter you can ask questions from your respective professor.

# Definitions :

**SET** - {} - is a collection of well-defined objects called elements ().

**SUBSET** - () - a set A is said to be a subset of another set B if every element of A is also an element of B.

**PROPER SUBSET** () - a set of A is said to be a proper subset of another set B,and there is at least one element in set B not in set A.

**NULL SET** - {} - a set which does not contain any element.

**UNION** - (U) - a set which contain elements in set A or in set B.

**INTERSECTION** - () - when one or more elements of set A also found in set B or intersection of set A and B. The intersection of two sets is the set of elements that are contained in two sets.

**DISJOINT SET** - when the intersection of two sets is an empty set.

**UNIVERSAL SET** - WHEN THE INTERSECTION OF TWO SETS IS AN EMPTY SET.

**FINITE SET** - the set whose elements can be counted.

**INFINITE SET** - the set...